Concentration of oxidized minerals



Patented Sept. 4, 1934 UNITED STATES 1,972,247 CONCENTRATION OF OXIDIZED MINERALS Ralph E. Sayre, Middlesex County, N. J., assignor to American Smelting & RefiningCompany, a corporation oi. New Jersey No Drawing.

Application June 20, 1931,

Serial No. 545,838

29 Claims.

This invention relates to the concentration of ores and has for an object the provision of an improved process for concentrating oxidized ores.

The present invention is based on my discovery that substances belonging to the class of compounds known as dithiocarbamates may be employed effectively in the concentration of oxidized ores by froth flotation. Dithiocarbamates and their salts such, for example, as their alkali metal salts may be employed in carrying out the process of the invention.

Dithiocarbamates for use in carrying out the process of the invention may be prepared in any suitable manner.

ient procedure for preparing such compounds consists in adding an alkali metal sulphide to a mixture of carbon bisulphide and an amine.

Thus, for example, sodium a-naphthyl-dithiocarbamate may be prepared by adding sodium sulphide to a mixture of a-naphthylamine and carbon bisulphide.

In order to obtain the reaction product in solid form, it is usually desirable to treat the reaction mixture with ether or with some other solvent in which the dithiocarbamate is but slightly soluble. It is not necessary for the purposes of the present invention to isolate the dithiocarbamate from the reaction mixture Thus, in the practice of the present invention, the dithiocarbamates may be used as crude reaction products without being isolated from the reaction mixture.

The alkali and alkylammonium salts of substituted dithiocarbamic acids are in general readily soluble in water and alcohol. The heavy metal salts (such as lead, zinc, iron, etc. salts) may be obtained as precipitates by treating the dissolved dithiocarbamates (such as the alkali and alkylammonium dithiocarbamates) with a dissolved salt of the heavy metal. Thus, for example, lead phenyl dithiocarbamate is produced by mixing solutions of lead acetate and potassium phenyl dithiocarbamate. In general, the heavy metal dithiocarbamates are only sparingly soluble even in hot water.

The process of the invention is particularly suitable for the concentration of ores containing silicate and carbonate minerals. In general, the amount of reagent required is from about 0.5 to about 2.0 pounds per ton of dry ore. In treating most ores, a frothing agent such, for example, as

pine oil is required.

The reagents may be incorporated in the flotationpulp at any suitable stage of the flotation operation, or they may be added prior to the final wet grinding operation. Relatively pure com- In general, the most conven-' pounds or products of reactions designed to produce such compounds may be added to the pulp directly or in solution in suitable solvents. Thus, for example, water soluble compounds such as sodium a-naphthyl-dithiocarbamate may be employed in the form of concentrated aqueous solutions.

As a general rule, it is advisable'to add the reagent in successive portions at intervals of several minutes until the required amount has been added. The use of a filming agent such as sodium sulphide is sometimes desirable, and it is preferably added in successive portions at or immediately preceding the times at which the thiocarbamate additions are made. In carrying out the process of the invention, neutral and alkaline pulps may be employed. In general, the use of a slime-conditioning agent such as lime or sodium silicate is advantageous. Such agents may be added, conveniently, prior to the final wet grinding of the ore.

The following examples give typical results obtained in the treatment of ores containing copper and lead silicate and carbonate minerals:

Example I A 500 gram sample of Mason Valley copper ore containing practically all of its copper in the form of malachite and chrysocolla was ground with water to produce a pulp in which 89.4 percent of the particles were minus 200 mesh. The resulting pulp was subjected to a froth flotation operation for a period of 20 minutes in a Janney laboratory flotation machine.

The quantities of reagents employed results obtained were as follows:

and the Example II A 500 gram sample of Copper Basin copper ore containing practically all of its copper in the form of malachite and chrysocolla was ground with water to produce a pulp in which 85.2 percent of the particles were minus 200 mesh. The resulting pulp was subjected to a froth flotation operation for a period of 15 minutes in a Janney laboratory flotation machine.

The quantities of reagents employed and the results obtained were as follows:

flotation operation for a period of 20 minutes in the absence of sodium sulphide and in the presence of lime and an increased amount of sodium a-naphthyl-dithiocarbamate.

The quantities of reagents employed and the results obtained were as follows:

Reagents Lbs. per ton of dry ore Sodium a-naphthyl-dithlocarbamate 2. 0 Sodium s onto 3. 0 Sodium sulphide (NmSAlH O) 2. 0 Pine oil 0. 14

Percent Percent Cu recovery Example III A 500 gram sample of Miami copper ore containing practically all of its copper in the form of chrysocolla was ground with water to produce a pulp in which 84.3 percent of the particles were minus 200 mesh. The resulting pulp was subjected to a froth flotation operation for a period of 12 minutes in a Janney laboratory flotation machine;

The quantities of reagents employed and the results obtained were as follows:

Reagents Lbs. per.ton of dry ore Sodium a-naphthyl-dithiocarbamate 1.0 Sodium silicate l. 0 Sodium sulphide (N818.9H10) l. 0 Pine oil 0. 14

Percent Percent Cu recovery Heads 1. 75 10.81 74. 9 ailings 0. so

Example IV A 500 gram sample of Utah Copper Company copper ore containing practically all of its copper in the form of malachite and azurite was ground with water to produce a pulp in which 75.2 percent of the particles were minus 200 mesh. The resulting pulp was subjected to a froth flotation operation for a period of 15 minutes in a Janney laboratory flotation machine.

The quantities of reagents employed and the results obtained were as follows:

Reagents Lbs. per ton of dry ore Sodium aaphthyl-ditbiocarbamate l. 2 Sodium silicate 1. 0 Sodium sulphide (NaySAlHzO) 1. 0 Pine oil'. 0. 14

Percent Percent Cu recovery Home l. 81 Concentrates 13. 47 77. 5 Tailings 0. 46

Example V Another 500 gram sample of the Utah Copper Company ore, in a pulp corresponding to that employed in Example IV, was subjected to a similar Reagents Lbs. per tan 0! dry ore Sodium a-naphthyl-dithiocarbamate- 2. 0 Lime 0H),) 0.3 Pine Oil 0. 14

Percent re- Percent Cu covers,

Heads 1. 81 Concentrates 13. 47 76. 7 'Inilimm 0. 47

Example VI A third 500 gram sample of the Utah Copper Company ore, in a pulp corresponding to'that employed in Example IV, was subjected to a similar flotation operation for a period of 20 minutes in the absence of sulphide and in the presence of sodium silicate and an increased amount of sodium a-naphthyl-dithiocarbamate.

The quantities of reagents employed and the Example VII A 500 gram sample of Yellow Pine lead ore containing practically all of its lead in the form of cerussite was ground with water to produce a pulp in which 89.2 percent of the particles were minus 200 mesh. The resulting pulp was subjected to a froth flotation operation for a period of 15 minutes in a Janney laboratory flotation machine.

The quantities of reagents employed and the results obtained were as follows:

Reagents Lbs. per ton of dry ore Sodium a-naphthyl-dithicarbamate. 0. 6 Sodium sulphide (NihSQHgO) 6. 0 Pine oil 0. 14

Percent re- Percent Pb covery Heads 6. 67 Concentrates 40. 20 77. 3 Teilings l. 51

In each of the tests reported above, a pulp containing about 20% solids by weight was employed. The slime conditioning agents such. as lime and sodium silicate were added to the pulp during the grinding operations. The remaining reagents were added in small amounts at short intervals during the course of the flotation operations.

I claim:

1. The process of concentrating oxidized ore which comprises subjecting the ore in the form of a pulp to a froth flotation operation in the presence of an a.-naphthyl-dithiocarbamate.

2. The process of concentrating oxidized ore which comprises subjecting the ore in the form of a pulp to a froth flotation operation in the presence of an alkali metal salt of a-naphthyldithiocarbamic acid.

3. The process'of concentrating oxidized ore which comprises subjecting the ore in the form of a pulp to a froth flotation operation in the presence of sodium a-naphthyl-dithiocarbamate.

4. The process of concentrating oxidized copper ore which comprises subjecting the ore in the form of a pulp to a froth flotation operation in the presence of an a-naphthyl-dithiocarbamate..

5. The process of concentrating oxidized lead ore which comprises subjecting the lead ore in the form of a pulp to a froth flotation operation in the presence of an a-naphthyl-dithiocarbamate.

6. The process of concentrating copper silicate ore which comprises subjecting the ore in the form of a pulp to a froth flotation operation in the presence of sodium a-naphthyl-dithiocarbamate.

7. The process of concentrating copper carbonate ore which comprises subjecting the are in the form of a pulp to a froth flotation operation in the presence of sodium a-naphthyl-dithiocarbamate.

8. The process of concentrating lead carbonate ore which comprises subjecting the ore in the form of a pulp to a froth flotation operation in the presence of sodium a-naphthyl-dithiocarbamate.

9. The process of concentrating oxidized ore containing the mineral chrysocolla which comprises subjecting the ore in the form of a pulp to a froth flotation operation in the presence of an a-naphthyl-dithiocarbamate.

10. The process of concentrating oxidized ore containing the mineral malachite which comprises subjecting the ore in the form of a pulp to a froth flotation operation in the presence of an a-naphthyl-dithiocarbamate.

11. The process of concentrating oxidized ore containing the mineral cerussite which comprises subjecting the ore in the form of a pulp to a froth flotation operation in the presence of an a-naphthyl-dithiocarbamate.

12. The process of concentrating ox'dized ore containing the mineral chrysocolla whichcomprises subjecting the ore in the form of a pulp to a froth flotation operation in the presence of sodium a-naphthyl-dithiocarbamate.

13. The process of concentrating oxidized ore containing the mineral malachite whch comprises subjecting the ore in the form of a pulp to a froth flotation operation in the presence of sodium a-naphthyl-dithiocarbamate.

14. The process of concentrating oxidized ore containing the mineral cerussite which comprses subjecting the ore in the form of a pulp to a froth flotation operation in the presence of sodium a-naphthyl-dithiocarbamate.

15. The process of concentrating ores of the type of oxidized lead and oxidized copper ores which comprises. subjecting the ore in the form of a pulp to a froth flotation operation in the presence of a sulphide filming agent and about 0.5 to 2.0 pounds of a dithiocarbamate per ton of dry ore.

16. The process of concentrating ores of the type of oxidized lead and oxidized copper ores which comprises subjecting the ore in the form of a pulp to a froth flotation operation in the presence of a sulphide filming agent, a slime conditioning agent and about 0.5 to 2.0 pounds of a dithiocarbamate per ton of dry ore.

17. The process of concentrating oxidized ore containing one or more minerals of the group consisting of malachite, azurite, cerussite and chrysocolla which comprises subjecting the ore in the form of a pulp to a froth flotation operation in the presence of a sulphide filming agent and about 0.5 to 2.0 pounds of a dithiocarbamate per ton of dry ore.

18. The process of concentrating oxidized ore containing one or more minerals of the group consisiting of malachite, azurite, cerussite and chrysocolla which comprises subjecting the ore in the form of a pulp to a froth flotation .operation in the presence of a sulphide filming agent, a slime conditioning agent and about 0.5 to 2.0 pounds of a dithiocarbamate per ton of dry ore.

18. The process of concentrating oxidized ore containing one or more minerals of the group consisting of malachite, azurite, cerussite and chrysocolla which comprises subjecting the ore in the form of a pulp to a froth flotation operation in the presence of about 0.5 to 2.0 pounds of an alkali metal dithiocarbamate per ton of dry ore.

20. The process of concentrating oxidized ore containing one or more minerals of the group consisting of malachite, azurite, cerussite and chrysocolla which comprises subjecting the ore in the form of a pulp to a froth flotation operation in the presence of a sulphide filming agent and about 0.5 to 2.0 pounds of an alkali metal dithiocarbamate per ton of dry ore.

21. The process of concentrating oxidized ore containing one or more minerals of the group consisting of malachite, azurite, cerussite and chrysocolla which comprises subjecting the ore in the form of a pulp to a froth flotation operation in the presence of a slime conditioning agent and about 0.5 to 2.0 pounds of an alkali metal dithiocarbamate per ton of dry ore.

22. The process of concentrating oxidized ore containing one or more minerals of the group consisting of malachite, azurite, cerussite and chrysocolla which comprises subjecting the ore in the form of a pulp to a froth flotation operation in the presence of a sulphide filming agent, a slime conditioning agent and about 0.5 to 2.0 pounds of an alkali metal dithiocarbamate per ton of dry ore.

23. The process of concentrating oxidized ore containing one or more minerals ofthe group consisting of malachite, azurite, cerussite and chrysocolla which comprises subjecting the ore in the form of a pulp to a froth flotation operation in the presence of an alkali metal dithiocarbamate.

24. The process of concentrating oxidized ore containing one or more minerals of the group consisting of malachite, azurite, cerussite and chrysocolla which comprises subjecting the ore in the form of a pulp to a froth flotation operation in the presence of a sulphide filming agent and an alkali metal dithiocarbamate.

25. The process of concentrating oxidized ore containing one or more minerals of the group consisting of malachite, azurite, cerussite and chrysocolla which comprises subjecting the ore in the tom of a pulp to a froth flotation operation in the presence of a slime conditioning agent and an alkali metal dithiocarbamate.

26. The process of concentrating oxidized ore containing one or more minerals of the group consisting of malachite, azurite, cerussite and chrysocolla which comprises subjecting the ore in the form of a pulp to a froth flotation operation in the presence of a sulphide filming agent, a slime conditioning agent and an alkali metal dithiocarbamate.

27. A process of concentrating oxidized ore containing the mineral malachite, which com- 

